Awwal 25, 1432 H/Feb 28, 2011, SPA -- The last known US veteran of the World War I has died at the age of 110, a spokesman said Monday, according to dpa. Frank Buckles died of natural causes Sunday at his home in Charles Town, West Virginia, family spokesman David DeJonge said in a statement posted on a website honoring Buckles. Born in 1901, Buckles joined the military at age 16. He had long advocated for the construction of a World War I memorial in Washington to pay tribute to American soldiers who fought in the conflict.